Various cleaning sponges have been developed incorporating a scrubbing surface within a polyurethane or other polymeric sponge. U.S. Pat. No. 3,414,928 issued to Lemelson shows a sponge containing plastic or wire wool embedded into the surface of a polyurethane or polyacetate sponge; U.S. Pat. No. 3,570,036 issued to Gilchrist shows a multiple layer polyurethane sponge, the surface layers comprised of alternating polyurethane laminar strips of differing textures. These sponges contain neither a particulate abrasive nor a detergent integral to the cellular matrix of the polymeric material. Similarly, British Pat. No. 955,713 discloses a layered sponge, one layer consisting of a steel wool abrasive surface. Richter U.S. Pat. No. 3,810,841 demonstrates that at least some abrasives as well as other additives, such as soaps and detergents, may be incorporated integrally into a polyurethane sponge having at least one reticulated layer for egress of additives. However, Richter's sponge not only has a different cellular structure than the product disclosed herein, but is produced by an altogether different procedure. Richter's sponge is to be used once for a surgical scrub; heavy duty use such as scouring kitchen utensils and appliances is neither contemplated nor practical.
A strong, long lasting, resilient polyurethane cleaning pad preferably should have a scouring abrasive concentrated near the surface, and the scouring surface should be textured to increase the active scouring area thereby reducing time and effort expended during cleaning. Unfortunately, a textured surface that increases active scouring area necessarily decreases strength, especially along the walls of the adjacent indentations. However, the pads of the present invention can be textured easily without overly sacrificing strength and permit the incorporation of abrasive at the surface in a manner that strengthens the walls of adjacent indentations. Furthermore, the pads of the present invention may also incorporate ample quantities of a detergent and other additives so that pad may be used many times before the supply of additives is exhausted.